Review of Cloud Feedbacks in Climate Models

An assessment of the current state of knowledge of cloud feedbacks in global climate models, their physical underpinnings and sources of uncertainty.

Science

RGCM-funded scientists contributed to an article reviewing the current state of knowledge of cloud feedbacks in global climate models. The authors review the primary cloud feedbacks in global climate models, explain how they are diagnosed, describe their underlying physical mechanisms, characterize how well these mechanisms are represented in models, and discuss the various sources of inter-model spread. The authors describe the extent to which each feedback is supported by theory, high-resolution modeling, and/or observations.

Impact

Cloud feedback – the change in planetary heating resulting from the cloud response to global warming – constitutes by far the largest source of uncertainty in the climate response to carbon dioxide forcing simulated by global climate models (GCMs). This article provides a much needed review of the state of scientific understanding of cloud feedback mechanisms that operate in climate models. The article describes recent advances in diagnostics, in the theoretical and observational basis for feedbacks, and in observational constraints on feedback sign and strength, while also providing an outlook of areas in need of continued research at the frontiers of the science.